JP4472092B2 - Induction synchronous reluctance motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reluctance type synchronous rotating machine that can be started by induction synchronization.
[0002]
[Prior art]
The induction synchronous type reluctance motor in which aluminum is die-cast into salient pole type multi-layer slit holes has a multi-layer slit structure to improve the efficiency and power factor. It is required to reduce the distance from the diameter (hereinafter referred to as slit bridge width).
[0003]
However, if the slit bridge portion is narrowed, stress is applied to the slit bridge portion due to centrifugal force, and the rotor is destroyed as the rotational speed (speed) increases. Or even if it does not break immediately when the rotation speed increases, it may break down due to repeated starting and stopping.
[0004]
As an example to solve such a problem, as described in Japanese Patent Application Laid-Open No. 11-146615, an induction-synchronous reluctance motor has a secondary conductor that passes through a slit hole. It is being used.
[0005]
[Problems to be solved by the invention]
However, in the conventional method, no consideration is given to the thermal expansion of the end ring portion and the secondary conductor. For this reason, when the secondary conductor is formed by aluminum die casting or the like generally used in induction motors, the slit bridge part, especially the end ring, is caused by the thermal fatigue cycle caused by the difference in thermal expansion coefficient between the aluminum material and the laminated steel sheet. The thermal stress applied to the laminated magnetic steel sheet in the vicinity of the part is large, and the slit bridge part may be destroyed.
[0006]
In addition, when the motor shaft length is long, the secondary conductor itself expands in a drum shape due to centrifugal force, and sufficient strength for holding the laminated steel sheet cannot be secured, and centrifugal force is large in large machines and high speed machines. If it becomes, the intensity | strength of the axial center part of a rotor will run short.
[0007]
The present invention has been made in view of such problems of the prior art. The secondary conductor can withstand thermal stress even if it is die-cast with a metal having a higher coefficient of thermal expansion such as aluminum than iron. An object of the present invention is to provide an induction-synchronous reluctance motor having a robust rotor that can withstand centrifugal force even when rotating at high speed.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, an induction-synchronous reluctance motor according to claim 1 of the present invention includes a stator having a multiphase coil winding that generates a traveling magnetic field of two or more poles,
A thin plate in which four or more layers of multi-layer slit holes having the same number of pairs as the number of poles of the stator are provided, and the bridge portion formed in the outermost peripheral portion of the rotor of each layer of the multi-layer slit holes is narrowed A rotor composed of a magnetic core stack in which magnetic saliency is formed by laminating magnetic steel plates;
Magnetic strength member having a hole which has a slit bridge portion which is wider reduction than thin magnetic steel plates of the magnetic core stack at both ends of the laminated core stack, and penetrates into the multilayered slit portions and the axial direction of the thin magnetic steel plates Place
Furthermore, and it is created by filling the aluminum multilayer slit portion by aluminum die-casting, and secondary conductor comprising a circular end ring shaft end portion which is formed integrally of the multilayer slit portion, in a configuration having the non The magnetic strength member is disposed at a position sandwiched between the laminated core stack and the annular end ring in the axial direction .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0011]
Embodiment 1.
FIG. 1 is a perspective view showing the configuration of the lamination of rotors of an induction synchronous reluctance motor according to the first exemplary embodiment of the present invention. 1 is a magnetic core stack in which thin magnetic steel plates 5 (electromagnetic steel plates) are laminated, 2 is a non-magnetic strength member disposed at both ends of the shaft of the core stack, and 3 is passed through 1 and 2 by die casting such as aluminum. An end ring integrally formed with the secondary conductor. Reference numeral 4 denotes a rotor shaft. In the induction-synchronous reluctance motor, the core stack shown in FIG. 1 rotates in a stator having a multiphase coil winding that generates a traveling magnetic field of two or more poles.
[0012]
Here, a cross-sectional view of a thin magnetic steel plate 5 constituting the core stack 1 is shown in FIG. FIG. 2B is an enlarged view of a portion A in FIG. In FIG. 2A, 7 is a slit serving as a flux barrier, and 8 is a slit bridge portion which is a thin portion at both ends of the slit. As shown in FIG. 2 (a), the magnetic steel plate 5 is formed with magnetic saliency by forming the same number of pairs of stator poles as the number of poles of the stator in the form of reverse arc-shaped multilayer slits with respect to the outer circumference circle. The width of the slit bridge portion indicated by δ in FIG. 2B is reduced to about the same as or less than the plate thickness to ensure the saliency of the rotor, and a rotor with high efficiency and power factor is obtained. It has gained.
[0013]
A cross-sectional view of the nonmagnetic material strength member 2 is shown in FIG. As shown in the figure, a reinforcing portion for dividing each multiphase slit is provided and the slit bridge portion is widened. Therefore, the strength is increased against centrifugal force and thermal stress. As a specific nonmagnetic strength member, an austenitic SUS, for example, SUS304, SUS301 or the like is used by being laminated. Since the SUS material has a higher strength against pulling than a general electromagnetic steel plate, the strength is also increased in terms of material. Moreover, since the coefficient of thermal expansion is close to that of an electromagnetic steel sheet as compared with aluminum, the generation of thermal stress with the electromagnetic steel sheet is small, and the thermal stress exerted on the electromagnetic steel sheet by thermal deformation of aluminum can be absorbed. Further, the same effect can be obtained even if the SUS material is made of an integrated block without being laminated.
[0014]
Further, the nonmagnetic strength member 2 is provided with a slit at a position penetrating the multilayer slit of the thin magnetic steel plate 5 in the axial direction. In particular, since the slits having a large cross-sectional area of the inner peripheral portion have almost the same area, even when the material 2 is sandwiched between the axial ends of the core stack in which the thin magnetic steel plates 5 are laminated, It is possible to prevent the strength member 2 from being damaged by the pressure of aluminum flow caused by die casting, or the formation of the secondary conductor from being incomplete due to insufficient die casting.
[0015]
Since the nonmagnetic strength member 2 arranged in this way holds the end ring against thermal stress even when the end ring part 3 is thermally expanded, it is possible to prevent the slit bridge part of the thin magnetic steel sheet 5 from being deformed. I can do it. Further, since the strength member is made of a nonmagnetic material, a leakage magnetic path is not formed even if it is disposed at the shaft end, and the performance of the reluctance motor is not deteriorated. In particular, as shown in FIG. 1, when an aluminum end ring portion is provided near the inner periphery of the rotor and all the slit portions of the core stack are filled with aluminum, a structure strong against centrifugal force can be obtained. However, on the other hand, the thermal stress caused by the end ring also increases accordingly. However, even in this case, since there is the nonmagnetic strength member 2 that holds the thermal stress of the end ring portion, the thermal stress can be suppressed. Therefore, a rotor for an induction-synchronous reluctance motor that satisfies both thermal stress and centrifugal force can be obtained.
[0016]
Embodiment 2. FIG.
FIG. 4 shows the configuration of the layers as seen from the side of the rotor of the induction synchronous reluctance motor according to the second embodiment of the present invention. The configuration of the shaft end is the same as that of FIG. 1 shown in the first embodiment.
[0017]
In the present invention, a reinforcing method for a case where the secondary conductor expands in a drum shape by rotation on a high speed machine or a large machine will be described. As shown in FIG. 4, the nonmagnetic strength member 6 is disposed at the central portion of the shaft. The cross-sectional shape of the strength member 6 is the same as that of the nonmagnetic strength member 2 at the shaft end, but is made of a nonmagnetic thin plate material such as SUS304 or SUS301. The nonmagnetic strength members 6 are alternately laminated with the thin magnetic steel plates 5.
[0018]
The reason why the nonmagnetic strength members 6 in the central portion of the shaft are alternately laminated and distributed with the thin magnetic steel plates 5 is to reduce the eddy current loss generated in the nonmagnetic strength members 6. At this time, even when the non-magnetic strength member 6 not subjected to the insulation treatment is sandwiched between the both sides of the thin magnetic steel plate 5 forming the magnetic core stack 1 by using the electromagnetic steel plates. Since the insulating material of the thin magnetic steel plate 5 prevents eddy currents due to lamination, eddy current loss due to harmonic magnetic flux such as stator slot harmonics can be prevented.
[0019]
Of course, the nonmagnetic strength member 2 at the shaft end and the nonmagnetic strength member 6 at the center of the shaft shown in FIG. 4 may be made of the same material. For example, six SUS304 materials having a cross-sectional shape shown in FIG. 3 are laminated on the shaft end to form a nonmagnetic strength member 2 having a thickness of 3 mm, and the same thickness as the strength member 6 is provided at the center of the shaft. 4 to 5 SUS304 materials having a thickness of 0.5 mm are alternately sandwiched between the thin magnetic steel plates 5 and laminated. In this case, since the non-magnetic strength member 6 at the center of the shaft and the non-magnetic strength member 2 at the shaft end can be obtained with the same member, the parts can be shared and created by press punching or the like. Sometimes the number of molds can be reduced, so that an inexpensive rotor excellent in mass productivity can be obtained.
[0020]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
[0021]
According to the induction-synchronous reluctance motor according to claim 1 of the present invention, a stator having a multi-phase coil winding that generates a traveling magnetic field of two or more poles, and a reverse arc shape having the same number of sets as the number of poles of the stator. The magnetic saliency is formed by laminating thin magnetic steel plates each having four or more multilayer slit holes, and the bridge portion formed at the outermost peripheral portion of the rotor of each layer of the multilayer slit holes having a narrow width. A non-magnetic strength member having a bridge portion wider than the thin magnetic steel plate of the core stack on the rotor constituted by the core stack, and having a multi-hole slit portion of the thin magnetic steel plate and a hole penetrating in the axial direction. After the laminated core stack is laminated on both ends, the multilayer slit portion is filled with aluminum by aluminum die casting, and the shaft end portion has a secondary conductor in which an annular end ring is integrally formed at the same time. It is provided with a stage.
[0022]
Therefore, the thermal stress of the end ring portion is held by the nonmagnetic strength member to prevent the slit bridge portion of the thin magnetic steel plate from being damaged due to the thermal stress, and the nonmagnetic strength member is die-casted for centrifugal force 2 Since it becomes a cage-shaped reinforcing member together with the secondary conductor, expansion due to the centrifugal force of the core stack can be suppressed, and a robust rotor for an induction-synchronous reluctance motor can be obtained.
[0024]
Also, thin plate-like non-magnetic strength members are alternately laminated with insulated thin magnetic steel sheets, so that loss due to eddy currents can be suppressed, and a rotor of an induction synchronous reluctance motor that is robust and has little loss can be obtained. I can do it.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a configuration of a rotor of a reluctance motor according to a first embodiment of the present invention.
2 is a cross-sectional view of a thin magnetic steel plate 5 forming a magnetic core stack 1. FIG.
3 is a cross-sectional view of a nonmagnetic strength member 2. FIG.
FIG. 4 is a side view showing a configuration of a rotor of a reluctance motor according to Embodiment 2 of the present invention.
1 Magnetic core stack, 2 Non-magnetic strength member, 3 End ring, 4 shaft,
5 Thin magnetic steel plate, 6 Nonmagnetic strength member, 7 Slit, 8 Slit bridge.

Claims (1)

A stator having a multiphase coil winding that generates a traveling magnetic field of two or more poles;
A thin plate in which four or more layers of multi-layer slit holes having the same number of pairs as the number of poles of the stator are provided, and the bridge portion formed in the outermost peripheral portion of the rotor of each layer of the multi-layer slit holes is narrowed A rotor composed of a magnetic core stack in which magnetic saliency is formed by laminating magnetic steel plates;
A non-magnetic strength member having slit bridge portions wider than the thin magnetic steel plate of the magnetic core stack at both ends of the laminated core stack , and a hole penetrating in the axial direction with each multilayer slit portion of the thin magnetic steel plate Place
Furthermore, and it is created by filling the aluminum multilayer slit portion by aluminum die-casting, and secondary conductor comprising a circular end ring shaft end portion which is formed integrally of the multilayer slit portion, in a configuration having the non An induction-synchronous reluctance motor characterized in that the magnetic strength member is disposed at a position sandwiched between the laminated core stack and the annular end ring in the axial direction .

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